![Enter title of presentation here Enter author’s names here If University Logo is required, please adjust size to fit below the line, e.g. Hydrogen Spillover Effect in the Fischer-Tropsch Synthesis The role of platinum as a promoter on cobalt-based catalysts Doreen Nabaho , Eric van Steen, Michael Claeys Centre for Catalysis Research, Department of Chemical Engineering University of Cape Town, Private Bag X3, Rondebosch, 7701, RSA E-mail : [email_address]](https://image.slidesharecdn.com/doreennabahocchangecatsa9nov-13109485662576-phpapp02-110717192618-phpapp02/85/Doreen-Nabaho-Cchange-amp-Catsa9-Nov-1-320.jpg)
![Dry M.E. Hydrocarbon Processing 61 (1982) 121 - 124. ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Low Temperature Fischer-Tropsch: Cobalt-based catalyst Goal: to elucidate the behaviour of the cobalt-based Fischer-Tropsch catalyst](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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Doreen Nabaho Cchange&Catsa9 Nov
- 1. Enter title of presentation here Enter author’s names here If University Logo is required, please adjust size to fit below the line, e.g. Hydrogen Spillover Effect in the Fischer-Tropsch Synthesis The role of platinum as a promoter on cobalt-based catalysts Doreen Nabaho , Eric van Steen, Michael Claeys Centre for Catalysis Research, Department of Chemical Engineering University of Cape Town, Private Bag X3, Rondebosch, 7701, RSA E-mail : [email_address]
- 20. ACKNOWLEDGEMENTS Insert University Collaboration Logo’s Here, e.g. Questions & Comments? Department of Science and Technology
Editor's Notes
- Carbon efficiency of GTL Plant = 57-70% Vs 90% in refineries : http://www.fosterwheeler.com/publications/tech_papers/files/IChemE%20WCCE%2005%20LNG%20versus%20GTL.pdf http://findarticles.com/p/articles/mi_m0CYH/is_20_4/ai_67316759/ GTL Fuels burn more cleanly: http://www.ifandp.com/article/00210.html Fluctuating costs: Most of the plants that were proposed in Qatar have been cancelled (ConocoPhillips and Marathon in Qatar, and all other Nigerian plants) or converted to LNG projects (ExxonMobil’s plant in Qatar). Energy intensive so that the plant is using 40% of the gas Advances in cat tech have helped inspite of this process being expensive + energy intensive
- Oukaci et al. (1999) carried out an overview of the current generation of patented cobalt-based Fischer-Tropsch catalysts. A summary of the general chemical characteristics of the catalysts that were reviewed is shown in Table 1. give e.g of oxide, support,noble metal
- Vannice, 1975; van Santen et al. -in press) (Weng et al., 1992; Delmon et al., 1994; Baeza et al., 2006)
- with Pt, Co 3 O 4 reduce at lower T & so a larger fraction form Co 0 at reduction conditions higher degree of reduction results in a higher dispersion and thus higher activity
- Surface mobility of reacting species and intermediates is a well known phenomenon and has been observed for other compounds such as oxygen, carbon monoxide, nitrogen and even organic species over distances of up to several millimeters (Weng et al., 1992; Delmon et al., 1994; Baeza et al., 2006).
- Based on the properties of spillover hydrogen, it was expected that during reduction, hydrogen would initially dissociate on the platinum surface to alumina from where secondary spillover would occur to the cobalt surface and induce reduction.
- Mentioned that catalysts are unreduced here.
- Say: for the sake of today’s study, I’d like to present the results this way…
- Briefly talk about peak identification
- NB: Prior to Fischer-Tropsch: Non-hybrid catalyst samples (Co/Al 2 O 3 , Pt/Al 2 O 3 ) also crushed in micronising mill for consistency in comparison with Pt-Co hybrid Degree of Reduction calculated based on milled catalysts
- DOR needed for TON When I refer to hybrid I mean milled
- TON calculated based on loaded amount of cobalt
- Further indication of possible saturation of platinum surface by carbon monoxide
- Points to CO hydrogenation
- Due to exp relationship Precovered by other intermediates It is therefore likely that hydrogen is involved in the rate determining step of the Fischer-Tropsch synthesis; meaning that one could effectively increase the reaction rate by delivering more hydrogen to the active surface during Fischer-Tropsch by hydrogen spillover. A point to note is that when delivering more hydrogen to the active surface, there is a trade-off between increasing the olefin readsorption and thus chain growth (an advantage) versus primary hydrogenation which would have the unwanted effect of decreasing the C 5+ selectivity.